DwmVariantFromIndex.hh

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//===========================================================================
// @(#) $DwmPath$
// @(#) $Id$
//===========================================================================
//  Copyright (c) Daniel W. McRobb 2020
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//---------------------------------------------------------------------------
//---------------------------------------------------------------------------
 
#ifndef _DWMVARIANTFROMINDEX_HH_
#define _DWMVARIANTFROMINDEX_HH_
 
#include <array>
#include <cassert>
#include <variant>
 
namespace Dwm {
 
  //------------------------------------------------------------------------
  //------------------------------------------------------------------------
  template <typename... Ts>
  std::variant<Ts...> VariantFromIndex(size_t index)
  {
    assert(index < sizeof...(Ts));
    static constexpr auto  tbl =
      std::array{ +[](){ return std::variant<Ts...>{Ts{ }}; }... };
    return tbl[index]();
  }
    
  
}  // namespace Dwm
 
#endif  // _DWMVARIANTFROMINDEX_HH_